Function printWarning

lib/assets/react-source/development/react.js:683–720

(level, format, args)

	}

	function printWarning(level, format, args) {
	  // When changing this logic, you might want to also
	  // update consoleWithStackDev.www.js as well.
	  {
	    var hasExistingStack = args.length > 0 && typeof args[args.length - 1] === 'string' && args[args.length - 1].indexOf('\n    in') === 0;

	    if (!hasExistingStack) {
	      var ReactDebugCurrentFrame = ReactSharedInternals.ReactDebugCurrentFrame;
	      var stack = ReactDebugCurrentFrame.getStackAddendum();

	      if (stack !== '') {
	        format += '%s';
	        args = args.concat([stack]);
	      }
	    }

	    var argsWithFormat = args.map(function (item) {
	      return '' + item;
	    }); // Careful: RN currently depends on this prefix

	    argsWithFormat.unshift('Warning: ' + format); // We intentionally don't use spread (or .apply) directly because it
	    // breaks IE9: https://github.com/facebook/react/issues/13610
	    // eslint-disable-next-line react-internal/no-production-logging

	    Function.prototype.apply.call(console[level], console, argsWithFormat);

	    try {
	      // --- Welcome to debugging React ---
	      // This error was thrown as a convenience so that you can use this stack
	      // to find the callsite that caused this warning to fire.
	      var argIndex = 0;
	      var message = 'Warning: ' + format.replace(/%s/g, function () {
	        return args[argIndex++];
	      });
	      throw new Error(message);
	    } catch (x) {}
	  }
	}

	var didWarnStateUpdateForUnmountedComponent = {};